The present disclosure generally relates to support foundations for mattresses, and more particularly, to mattress assemblies including dual supporting layers for independent suspension.
Standard mattress designs have evolved very little in the past fifty years. A standard mattress generally includes a set of metal springs or coils mounted either on a base under a pad, or sandwiched in the center of a pair of pads. The metal springs and pad or pads are then covered with a strapping material. The entire structure is then sewn into a cloth cover and the edges are wrapped and sewn. Thus, once the mattress is fabricated, the components are not replaceable. The limitations of metal spring mattresses combined with improved quality and durability of foam products has lead to the relatively recent development of a foam core mattress as a viable alternative to metal spring mattress. A foam core mattress can provide significant improvements in comfort and support compared to conventional spring-based mattresses. For example, spring-based mattresses inherently have varying properties over their surface, and the variations of properties relating to zone and surface areas are improved only with great difficulty.
A basic foam mattress may include one or more layers of foam having desirable properties assembled into a fabric cover so as to appear identical in appearance to a standard metal spring mattress. A foam mattress may include a center core of relatively high resilience foam sandwiched between two layers of lower resilience foam encased in a fabric shell. This construction allows for a reversible mattress.
Mattress foundations such as box springs have also evolved relatively slowly. Foundations are often typically constructed of a combination of materials, including wood, metal, and fiber and may include support sub-assemblies such as edge-reinforcing springs. Typically, conventional box springs include a wooden frame that supports an array of steel wire springs that elevate a grid or deck above the frame to provide a flexible support surface. The grid or deck can be formed of steel wire that is welded or clipped together. A cloth outer cover is typically disposed about the frame. The conventional box springs are generally large, heavy, and provide minimal flexibility.
One of the disadvantages with mattresses, especially foam mattresses, is the perceived temperature and firmness of the mattress.